I think I finally found all the drain plugs for the 87 4kq tranny and rear diff, now I need to ask a couple of questions about the refill process.

1.The two drains up front; do they drain the same fluid or is there one fluid(GL4) for the tranny and another for the center diff(MT90)? If so, I'm having trouble fdinding the fill plug for the center diff. HOw many qts will they take? I think the rear diff is about a quart.
2. Since the plan is to replace the fluid with Redline, and the side seal for all 4 axles are leaking(rear diff is pretty wet), should I replace the seals before switching fluid and if so, how hard a job is it? I've done the job on my Vanagon, but that doesn't mean this willbe the same. Is it better to do this replacement with drivetrain in the vehicle or beytter to remove?

thanks

Max

There are 2 drain plugs at the front (trans and center diff), they both drain the same kind of fluid. There is only one fill plug, its found on the drivers side of the trans, large allen, ya cant miss it. What I did was get some clear hose and snake it to the top of the engine bay and pour it in that way. Keep in mind, gear oil is thick, so it takes a while.
Ive never replaced the seals that you mention of, but Im sure somebody has.

I bought some redline the other day and took a quick look underneath... only to be completely stumped as to how i'd go about filling itup.

I know it may sound obvious, but make sure you can get the filler plug out, BEFORE you drain!

Otherwise you'll end up with an empty trans, with no way to fill!

I've had plugs so stuck that I've had to use the torch to heat them up a bit. Usually didn't take too much heat to crack the steel plug loose from the aluminum trans case.

And pay attention to the GL4 & GL5 requirements(as per the Bently Manual).

GL4 ONLY for the transmission (GL5 is bad for synchros. Supposedly has more sulpher in it, so makes the synchros more brittle), and GL5 for the rear diff (where there are no synchros).

If the oil is both GL4/GL5 compatable, I'm not sure what the story is...?

THe proper 17mm (I think) tool is a worthwhile purchase (Allen key, or socket adaptor)...

Thanks for the feedback. I've always thought buying a couple cheap ketchup or mustard squeeze bottles from Wally World or a reataurant supply house and cuttingthe tip off so more flow can pass through it would be the trick for filling the rear differential. Yeah, you only get 8 or so oz. in at a time, but we're talking a liter capacity at most here, right? The long hose scenario worked on an old BMW 320i we had given to us some years ago.

The suggestion by one gentleman of using a 17mm wheel bolt and a vise grip to pop the fill and drain plugs is a great idea and I second the motion for popping ALL the fill and drain plugs prior to a fluid switch. Now that I know that there's only 1 fill plug for the tranny and one fluid for the front, I can proceed with peace of mind.

I think my questions have pretty much been answered. I think I'll post a more specific side cover seal question. The Vanagon side seals were pretty easy to do.

Thanks again.

Max